Cell surface carbohydrates are being studied in normal and diabetic humans and experimental animals. Erythrocytes are first fractionated by ultracentrifugation into cells of different density, which correlates with their age. Ghosts prepared from these cells are being analyzed for their carbohydrate and amino acid composition and their electrophoretic behavior in order to detect any differences caused by the diabetic state. The concentrations of various intermediates involved in the synthesis of glycoproteins and glycolipids are being measured in the tissues of normal and alloxan diabetic rats.